Willard Van Orman Quine’s Word and Object (1960) is a study in the philosophy of language, describing how linguistic analysis may be used as a method of resolving philosophical problems. Quine explains how uncertainty about the reality of concrete or abstract objects may be resolved by defining the relation between words and objects. Quine also presents a behaviorist theory of language, describing language as consisting of publicly-observable behavior. Language may develop as a complex system of behavioral dispositions to communicate thoughts or feelings in response to verbal or non-verbal stimuli.

Chapter I is concerned with the role that stimulus-response mechanisms may play in the acquisition of language. Chapter I critically examines the theory that the fundamental purpose of language is to describe our sensory perceptions of the world. Chapter I also questions the theory that the fundamental purpose of language is to describe how physical or abstract objects are related to reality.

Chapter II describes language as a system of dispositions to perform verbal behavior. Chapter II also explains how sentences may demonstrate synonymity of stimulus-meaning, and describes how the truth-functions of sentences may be translated. Chapter II also questions the validity of the distinction between analytic and synthetic sentences, and describes the causes of failure to perceive indeterminacy of translation.

Chapter III is concerned with the distinction between singular and general terms, and asserts that the distinction between singular and general terms is not based on how they are used to refer to objects, but on how they are used in predication (i.e. how they are used to assert something about the subject of a sentence or proposition).

Chapter IV explains how vagueness of the terms of a sentence or proposition may cause that sentence or proposition to have referential opacity.

Chapter V describes how freedom of variables involving the terms which are found within a sentence may cause the sentence to have referential opacity.

Chapter VI discusses the relation between propositions and meanings, and the relation between propositions and eternal sentences.

Chapter VII describes how 'semantic ascent' may lead us from a concern with objects to a concern with words. Chapter VII also explains how this strategy may enable us to avoid being confined to examining words as objects or objects as words.

Chapter VII also questions the distinction between Nominalism (the theory that there are no abstract or universal objects) and Realism (the theory that abstract or universal objects are real and that abstract or universal objects exist independently of our perceptions of them).

According to Quine, the acquisition of language is a process of conditioning the performance of verbal behavior. Words for concrete or abstract objects may be learned by a process of reinforcement and extinction, whereby the meaning of words may become more clearly understood.

Quine argues that the meaning of a sentence as a stimulus to verbal behavior is defined by what type of response it arouses in the listener or reader. A sentence may have an affirmative stimulus-meaning if it prompts a response of assent in the listener or reader. A sentence may have a negative stimulus-meaning if it prompts a response of dissent in the listener or reader.

Quine distinguishes between the functions of two kinds of sentences: 1) 'occasion sentences' (which assert something about a present or temporary occasion), and 2) 'standing sentences' (which assert something about a more permanent situation). According to Quine, the response to 'occasion sentences' may depend on prompting by simultaneous stimulation, but the response to 'standing sentences' may occur without prompting by simultaneous stimulation.

Quine also defines 'observation sentences' as standing sentences whose meanings are less susceptible than occasion sentences to the influence of intrusive information. While occasion sentences may have considerable variability of stimulus-meaning for various listeners or readers, observation sentences may have relative stability of meaning for various listeners or readers.

Quine explains that 'occasion sentences' may be synonymous with each other if they have the same stimulus-meaning. The stimulus-meaning of an occasion sentence may be increased by lengthening its modulus of stimulation, or may be decreased by shortening its modulus of stimulation.

The verbal responses to stimulus-meanings may be accessible to translation. 'Radical translation' of an occasion sentence may depend on the sentence's having the same stimulus-meaning in one language as in another. Indeterminacy of translation may occur if there is variability of a sentence’s stimulus-meaning between one language and another.

According to Quine, singular or general terms may be concrete or abstract, simple or compound, absolute or relative, definite or indefinite. Singular terms may refer to single objects, while general terms may refer to multiple objects. General terms may have divided reference, in that they may refer to more than one object.

However, Quine argues that the distinction between singular and general terms may be based on how they are used to construct sentences, rather than on how they are used to refer to objects. A general term may be predicated of a singular term (e.g. the general term "satellite of the earth" may be predicated of the singular term "the moon" in the sentence "the moon is a satellite of the earth"). At the same time, general terms may be converted into singular terms by demonstrative prefixes such as "this" or "that," as in "this sugar," or "that water."

Quine explains that if a singular term is used to refer to a person or thing, then sentence constructions which maintain the same referential use of that term have 'referential transparency.' If a singular term is used to refer to a person or thing, then sentence constructions which interrupt or discontinue the previous referential use of that term have 'referential opacity.' Thus, in a referentially-transparent sentence construction, a term which refers to an object may be replaced by a codesignative term (i.e. a term which refers to the same object), without changing the truth-value of the sentence. In a referentially-opaque sentence construction, however, the replacement of a term by a codesignative or coextensive term may often change the truth-value of the sentence.

Quine describes 'eternal sentences' as standing sentences whose truth-values remain constant over time, and whose truth-values remain constant from speaker to speaker.1 Non-eternal sentences are statements whose truth-values may change over a period of time, or whose truth-values may change from speaker to speaker. Standing sentences may be eternal or non-eternal.

Quine explains that the stimulus-meanings of eternal sentences may be propositions, and that synonymous eternal sentences may express identical propositions. Rather than describing propositions as abstract concepts, or as objects of propositional attitudes, Quine describes propositions as meanings of eternal sentences. Quine argues that it is not necessary for propositions to function as vehicles of truth for eternal sentences, because eternal sentences may express their own truth. Propositional abstraction may thus be an unnecessary philosophical strategy.